1. Field of the Invention
The present invention relates to medical devices and more particularly to an improved electroencephalogram (EEG) brain wave detection scalp electrode system.
2. Description of the Related Art
Conventional techniques for recording brain waves (electroencephalograms or EEGs) of a human subject require attaching electrodes to the scalp with a low impedance connection. This involves cleaning and abrading the scalp and applying a conducting gel or solution which makes the electrical contact between the scalp and the electrode. When performed manually, the procedure takes about 20 minutes for the 19 electrodes usually used in clinical EEG examinations. Computerized EEG systems are tending towards a larger number of channels in order to better sample the brain spatially, but are limited by the increased time and effort required to apply the electrodes. For example, the most advanced research EEG systems employ 128 electrodes which takes a team of technicians more than an hour to apply.
A prior attempt to automate EEG electrode application, by Johansson, Eralp and Itil (U.S. Pat. No. 4,683,892) is based on an electromechanical design which mechanized the manual scalp preparation procedure resulting in a complex, large and expensive apparatus.
This device, which looks like a hair dryer with 16 cylindrical protuberances, uses air pressure to push electrodes into contact with the scalp and pumps which dispense, and then retract, a cleaner and then dispense an electrode gel. The device, due to its bulk, mechanical complexity and expense, is not suitable for many application such as ambulatory monitoring, sleep studies, flight simulators, cockpits or field use.
In U.S. Pat. No. 4,709,702 to Sherwin, the electrodes contact the scalp with "tulip probes" having sharp points to "penetrate the dead skin layer". Such a sharp pointed tip is medically dangerous due to the dangers of infection and hurting the patient.